362
FXCA20 KWBC 211235
PMDCA
TROPICAL DISCUSSION - INTERNATIONAL DESKS
NWS WEATHER PREDICTION CENTER COLLEGE PARK MD
735 AM EST WED DEC 21 2022
PRELIMINARY DISCUSSION FOR PUERTO RICO AND THE USVI FROM DEC
21/12UTC: A BROAD MID-LEVEL RIDGE COVERS THE ENTIRE NORTHERN
CARIBBEAN WHILE CENTERING ON A HIGH OVER SOUTHEAST CUBA. THIS IS
SUSTAINING A TRADE WIND CAP...WHICH IS IN TERM LIMITING VERTICAL
DEVELOPMENT ACROSS THE REGION. ACTIVITY IS ORGANIZING IN WEAK
PERTURBATIONS PROPAGATING IN THE EASTERLY TRADES. ONE IS CROSSING
THE WESTERN VI ON WEDNESDAY MORNING AS EVIDENCED BY SATELLITE
IMAGERY. ASSOCIATED WITH THIS PERTURBATIONS...VERY LIGHT RAIN
SHOWERS ARE OCCURRING.
THE MID-LEVEL RIDGE IS FORECAST TO ROLL EASTWARD ACROSS THE
GREATER ANTILLES...TO SUSTAIN AN ENAHNCED TRADE WIND CAP
THROUGHOUT THE ENTIRE FORECAST CYCLE. IN THE UPPER LEVELS...A
RIDGE CURRENTLY OVER SOUTHERN CENTRAL AMERICA IS FORECAST TO
AMPLIFY INTO THE WEEKEND. THIS WILL LEAD TO THE AMPLIFICATION OF A
TROUGH TO ITS EAST...OVER THE TROPICAL ATLANTIC NORTHEAST OF THE
LEEWARD ISLANDS. THE AMPLIFICATION OF THIS TROUGH WILL FAVOR A
SLIGHT DESTABILIZATION OF THE MARINE LAYER TO THE EAST OF THE
ISLANDS...WHICH WILL RESULT IN ENHANCED VERTICAL DEVELOPMENT AND
LARGER RAINFALL RATES IN TRADE WIND CONVECTION THAT TRANSVERSES
THE REGION. YET...THE EFFECTS OF THE MID-LEVEL RIDGE WILL BE
DOMINANT AND NO SIGNIFICANT PRECIPITATION IS EXPECTED DURING THE
HOLIDAY AND INTO EARLY NEXT WEEK. ACCELERATED EASTERLY TRADES ARE
FORECAST THROUGH THE ENTIRE CYCLE...BUT AN INCREASE IN THE SURFACE
PRESSURES ACROSS THE NORTH ATLANTIC AROUND CHRITSMAS WILL FAVOR AN
ADDITIONAL INCREASE IN VELOCITY TO 25-30KT BY SUNDAY AND MONDAY.
THIS WILL FAVOR ENHANCED MORNING SHOWERS IN EASTERN PUERTO RICO
AND THE EASTERN SLOPES...AND LIMITED DIURNAL ACCUMULATIONS IN
AFTERNOON CONVECTION IN WESTERN AND NORTHWESTERN PUERTO RICO DUE
TO ENHANCED LOW-LEVEL SHEAR AND SHORT RESIDENCE TIMES.
GALVEZ/ACOSTA...WPC (USA)
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